Based on kernel version 4.3. Page generated on 2015-11-02 12:49 EST.
1 Kernel driver htu21 2 =================== 3 4 Supported chips: 5 * Measurement Specialties HTU21D 6 Prefix: 'htu21' 7 Addresses scanned: none 8 Datasheet: Publicly available at the Measurement Specialties website 9 http://www.meas-spec.com/downloads/HTU21D.pdf 10 11 12 Author: 13 William Markezana <william.markezana@meas-spec.com> 14 15 Description 16 ----------- 17 18 The HTU21D is a humidity and temperature sensor in a DFN package of 19 only 3 x 3 mm footprint and 0.9 mm height. 20 21 The devices communicate with the I2C protocol. All sensors are set to the 22 same I2C address 0x40, so an entry with I2C_BOARD_INFO("htu21", 0x40) can 23 be used in the board setup code. 24 25 This driver does not auto-detect devices. You will have to instantiate the 26 devices explicitly. Please see Documentation/i2c/instantiating-devices 27 for details. 28 29 sysfs-Interface 30 --------------- 31 32 temp1_input - temperature input 33 humidity1_input - humidity input 34 35 Notes 36 ----- 37 38 The driver uses the default resolution settings of 12 bit for humidity and 14 39 bit for temperature, which results in typical measurement times of 11 ms for 40 humidity and 44 ms for temperature. To keep self heating below 0.1 degree 41 Celsius, the device should not be active for more than 10% of the time. For 42 this reason, the driver performs no more than two measurements per second and 43 reports cached information if polled more frequently. 44 45 Different resolutions, the on-chip heater, using the CRC checksum and reading 46 the serial number are not supported yet.